§ 1.1 Field of the Invention
The present invention concerns delta-sigma error feedback (ΔΣ EF) modulators. More specifically, the present invention concerns noise transfer functions (NTFs) in ΔΣ EF modulators, particularly in ΔΣ EF modulators used in digital-to-analog converters (DACs) and phase-locked loops (PLLs).
§ 1.2 Background Information
Delta-sigma (ΔΣ) modulators are introduced in § 1.2.1 below. Then, the use of ΔΣ EF modulators in digital-to-analog converters (DACs) and phase-locked loops (PLLs) is introduced in § 1.2.2. Finally, challenges to designing well-performing ΔΣ EF modulators are discussed in § 1.2.3.